CO2 emissions correction of light-duty vehicles based on an energy deviation analysis method

- 3 types of light-duty vehicles were investigated by using a vehicle dynamics-based simulation method.
- Chassis dynamo test result was affected by deviation against target speed and inaccurate road load condition.
- The CO2 correlation method based on total work deviation was applied to reduce a relative error.
- When applying the correction method, the relative error of CO2 emission converged within 2% in all cases.
- CO2 correction method will be a good solution to advance reliability of chassis dynamometer test results.

In present study, a total of 3 types of light-duty vehicles were tested for 7 types of driving modes by using a vehicle dynamics-based simulation method. Deviations between the target and actual test vehicle speed and inaccurate chassis dynamometer road load settings are selected as the two main factors affecting the CO2 emission measurement test. 126 cases of simulations were conducted to analyze the effects of the deviation between the target and actual test vehicle speed on CO2 emissions and 63 cases of simulation were conducted to analyze the effectiveness of inaccurate road load test conditions on CO2 emissions. Then, the CO2 correlation method proposed by World Forum for Harmonization of Vehicle Regulations (WP.29, UN) was applied for simulated results in original simulation cases, and a correction to performance was validated by comparative analysis. From the simulation results, it is revealed that velocity and road load deviation are related to distinct changes in fuel efficiency and CO2 emission rates of test vehicles. Also, it is revealed that CO2 correction method show good performance to reduce the relative error lower than 2% in all test cases.